1. Field of the Invention
The present invention relates to a gear assembly which constitutes a single gear to be mated with a third gear to eliminate backlash therebetween, for reducing noise caused by mated gears. The present invention can be widely applied in a variety of mechanical fields.
2. Description of the Related Art
A conventional non-backlash gear assembly is known in which the assembly comprises two gears and a spring, each end of which is anchored to the respective gears to provide a circumferential force that will cause the two gears to rotate in opposite directions, so that this gear assembly can be mated with a third gear in a non-backlash manner.
Several types of springs are used for biasing the two gears. For example, a compression coil spring is used in the device shown in FIG. 2 of Japanese Examined Utility Model Publication (Kokoku) No. 48-34438 and in FIG. 1 of Japanese Unexamined Utility Model Publication (Kokai) No. 55-158349. A torsional coil spring is used in Japanese Unexamined Utility Model Publication (Kokai) No. 56-160351, and a C-shaped round steel spring is used in FIG. 1 of Japanese Examined Utility Model Publication (Kokoku) No. 48-34438 and in FIG. 3 of Japanese Unexamined Utility Model Publication (Kokai) No. 55-158349. Further, a hairpin shaped spring is used in Japanese Examined Utility Model Publication (Kokoku) Nos. 48-34438 and 48-2947.
In a known non-backlash gear assembly including a spring in the form of a C-shaped clip, two circular holes are provided in the spring adjacent to either end thereof and each of the two gears has one pin. Thus each end of the spring can be connected to each gear by the pin and circular hole. This known type of gear assembly has a disadvantage in that assembly is difficult. Namely, it is very cumbersome to fit the holes to the pins, as shown below. In the first step the spring is rested on the first gear, and the circular hole of one end of the spring is fitted to the pin on the first gear. This is very easy since both the first gear and the spring can be seen by the operator. In the second step, however, the second gear must be moved onto the first gear, to fit the pin on the second gear into the other hole of the spring. This is very cumbersome since the first gear, the spring and the other pin of the second gear cannot be seen because they are blocked by the second gear, and the operator must fit the other hole to the other pin by touch.